Lead-free no-clean flux issues: white residue

White residue is often oxidized rosin, flux salts, or rosinates that crystallize. It is visible after reflow and can:

• reduce conformal coating adhesion,

• indicate ionic contamination,

• accelerate corrosion in humid conditions.

Action: replicate production reflow in lab, analyze residues with FTIR or ion chromatography, and select cleaning solvents or fluxes optimized for lead-free processes. ZESTRON offers analytical services to identify white residue chemistr